Convert the s390 CPU to the Resettable interface. This is slightly
more involved than the other CPU types were (see commits
9130cade5fc22..d66e64dd006df) because S390 has its own set of
different kinds of reset with different behaviours that it needs to
trigger.
We handle this by adding these reset types to the Resettable
ResetType enum. Now instead of having an underlying implementation
of reset that is s390-specific and which might be called either
directly or via the DeviceClass::reset method, we can implement only
the Resettable hold phase method, and have the places that need to
trigger an s390-specific reset type do so by calling
resettable_reset().
The other option would have been to smuggle in the s390 reset
type via, for instance, a field in the CPU state that we set
in s390_do_cpu_initial_reset() etc and then examined in the
reset method, but doing it this way seems cleaner.
The motivation for this change is that this is the last caller
of the legacy device_class_set_parent_reset() function, and
removing that will let us clean up some glue code that we added
for the transition to three-phase reset.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Thomas Huth <thuth@redhat.com>
Message-id: 20240830145812.1967042-4-peter.maydell@linaro.org
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